Ink jet printers are a well known means for creating black and white and color images on a recording medium. The images are created by generating small droplets of ink which are propelled onto the recording medium. The ink generally contains a water-based dye or dispersed pigment and the recording medium is often paper, but it may also be a coated polymeric film, e.g., transparencies for overhead projectors. Advantages with this type of printing include the ability to create high-resolution, full-color images rapidly and in large formats using digitally generated and stored images. It is also quiet, environmentally friendly and safe. Inkjet printing, however, is not without certain difficulties
In inkjet printing, the ink has to be absorbed as quickly as possible by the recording medium in order to allow the recording medium to be handled soon after the ink has been applied without the ink diffusing or spreading too far through and into the recording medium. Such diffusion and spreading works against the production of images having photographic quality resolution.
Other difficulties with inkjet printing are that the image can lack water and abrasion resistance. These two problems, along with the lack of light fastness of the dyes that are commonly used in inkjet inks, can hinder the application of inkjet printing to products which require outdoor weatherability.
These and other difficulties are successfully addressed by the water-resistant, inkjet recording media topcoat compositions taught in U.S. Pat. No. 5,882,388. The compositions of this patent comprise (a) a binder composition comprising a non-cationic, water-insoluble binder resin having a high surface energy and dissolved or dispersed in an aqueous liquid medium, and (b) hydrophilic pigment particles having a number average particle size in the range from 1-25 microns and an oil absorption of at least 60 grams of oil per hundred grams of particles (g oil/g 100 particles). While the use of the recording media topcoats of this patent produce commercial quality images, a continuing interest exists in identifying recording media topcoats that not only increase the color density of the images, but also increases the definition of the images.